Field of the Invention
The present invention relates to an electrophotographic member to be used in an electrophotographic apparatus, a method of producing the electrophotographic member, and a process cartridge and an electrophotographic apparatus each including the electrophotographic member.
Description of the Related Art
In an electrophotographic apparatus (such as a copying machine, facsimile, or printer employing an electrophotographic system), first, a photosensitive member is charged by a charging unit, and an electrostatic latent image is formed on the photosensitive member by laser exposure. Then, a developer (hereinafter sometimes referred to as “toner”) in a developing container is conveyed by a developing member, and the electrostatic latent image on the photosensitive member is developed with the toner in a portion where the photosensitive member and the developing member are brought into close contact with each other. After that, the toner on the photosensitive member is transferred onto a recording sheet by a transferring unit and fixed onto the recording sheet with heat and a pressure.
In the electrophotographic apparatus, electrophotographic members, such as a developer carrying member, a charging member, a developer supplying/stripping member, a cleaning blade, and a developer regulating member, are used. Electro-conductive layers are arranged in some of those electrophotographic members.
In, for example, an electrophotographic image-forming process, the impartment of charge to the toner is performed by the friction of the toner between both or either of the following combinations: the developer carrying member and the developer regulating member; and/or the developer carrying member and the developer supplying/stripping member. Here, stable charging of the toner is important for the formation of a high-quality electrophotographic image.
In Japanese Patent Application Laid-Open No. 2004-333682, there is a disclosure of a developer carrying member including a substrate and a resin layer on the substrate, in which the resin layer is formed of a resin composition containing a silane coupling agent, and a binder resin that the resin layer contains has a copolymer of a vinyl polymerizable monomer and a nitrogen-containing vinyl monomer.
In addition, in Japanese Patent Application Laid-Open No. 2012-181367, as a developer carrying member that can stably impart charge to a toner even under a high-temperature and high-humidity environment, there is a disclosure of a developer carrying member whose surface layer contains: a copolymer having a constituent unit having a pyridinium structure and a constituent unit having a tertiary amino group; and polyurethane.
Further, in Japanese Patent Application Laid-Open No. 2013-33238, there is a disclosure of a developer carrying member including an elastic layer containing a silicone rubber and a surface layer covering the surface of the elastic layer, in which the surface layer contains a copolymer having: a constituent unit having a quaternary ammonium salt structure having a specific structure; and a tertiary amine structure having a specific structure.
An investigation made by the inventors of the present invention has confirmed that the developer carrying member according to the invention disclosed in each of the above-mentioned Japanese patent laid-open application publications is excellent in charge-imparting performance for a toner. However, as a result of their further investigation, the inventors of the present invention have found that when any such developer carrying member is placed under a high-temperature and high-humidity (e.g., a temperature of 40° C. and a relative humidity of 95% (hereinafter sometimes referred to as “95% RH”)) environment over a long time period, tackiness may be expressed on the surface of the developer carrying member. It is assumed that a toner sticks to the developer carrying member in which the tackiness has occurred on the surface to cause a defect in an electrophotographic image.